Need a guru! ZA50 assistance

Puch Newport with a ZA50, 70cc KStar, Proma Circuit, and 14mm Sha.

After a year of running perfectly, the moped all of a sudden stopped starting unless i turned it over super fast.

I replaced the carburetor and it kept doing the same thing. I put a new CDI on and timed it, keeps doing the same thing. Rebuilt the top end with new gaskets and torqued it to specs and the same thing. I've tried numerous jets and still the same results.

Getting blue spark, getting gas, plenty of compression...

It will only start if I pedal super fast while turning it over and will immediately die when i release the throttle.

Any suggestions?

Re: Need a guru! ZA50 assistance

Fuel flow clogged? New spark plug?

I've blown out the stator side seal on a couple of fast ZAs. If so, just pop it back in with some sealant on it.

Re: Need a guru! ZA50 assistance

the fuel flow is normal and i've replaced the plug at least 4 times.

I just removed the stator and the seal seems okay...should be set back into the case about a half inch or so?

Re: Need a guru! ZA50 assistance

What's you're compression reading?

Re: Need a guru! ZA50 assistance

Good question. I don't have a gauge or I'd have a precise PSI for you, but it's sucking my finger in with every rotation.

Feels the same as it did when it rode perfectly normal.

Re: Need a guru! ZA50 assistance

check your wiring, i know nothing about CDIs but if it has a condensor try replacing that

Re: Need a guru! ZA50 assistance

CDI doesn't have a condensor. BUT even if you have spark, how do you know it's timed correctly? Are you using a timing light?

Re: Need a guru! ZA50 assistance

I'd try and get my hands on a compression gauge.

In the mean time my suggestion is to put the points back on, to rule out your top end, carb etc. since you don't have a compression gauge and we don't know if you have a timing light.

Then, if it works, you'll know it's the cdi. If it doesn't, At least you know it's not the cdi.

You must have a timing light to time cdi - it is not a good idea or nice to have, it is essential.

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